Airspeed or Altitude?

Rob58

Rob58

Pre-takeoff checklist
Joined
Feb 20, 2016
Messages
369
Display Name
Display name:
Rob
Would like to get some opinions... on a departure what is more valuable in case of a power loss: airspeed or altitude?
 
Yea altitude for me, more time to figure out a potential landing area.
 
You are gonna trade the airspeed for altitude anyways. So altitude.
 
Rob58 said:
Would like to get some opinions... on a departure what is more valuable in case of a power loss: airspeed or altitude?
Click to expand...
Single or twin?

Speed is life. I'll take speed.
 
Just realize if you're going to depart at Vx, you will have to nose over even more aggressively than you would at Vy to keep flying should you lose the engine.
 
The problem with "airspeed" is that parasitic drag increases as the square of the increase in velocity. Achieving a bunch of extra airspeed with the intent of a "zoom climb" if something goes wrong will always put you at a lower altitude than just climbing at Vy or Vx as appropriate, and hence give you fewer options.

So: altitude.
 
Altitude, to a point.

Stalling the aircraft is not a good option. Use Vy unless you have an obstacle or minimum climb angle that requires Vx.
 
You can easy trade potential energy into cinetic energy just pushing down. Altough the other way is possible, its way less efficient and intuitive.
At the end, you need to have zero of both to deplane!
 
Both are equally important, but I would also say altitude. Gives the most options, and also gives you some airspeed as well. I've tried to get into the habit of briefing engine failure on takeoff before every flight. Know where the best "outs" are and what you will do if the engine pukes at a certain time of the T/O phase.
 
MAKG1 said:
Stalling the aircraft is not a good option. Use Vy unless you have an obstacle or minimum climb angle that requires Vx.
Click to expand...
Less altitude gives you less time to think about it. Less airspeed means you have to act now, out of training/reflex to keep the airplane flying.

50 feet & Vx means you have about enough time to think, "Oh ****!" and "This can't be happening to me!" while your training shoves the nose down and then pulls back to land. Oh, yeah...there was some thought about making sure the shoulder harness was latched...
 
Climbing out at Vx once you're over any obstacles doesn't make much sense, Vy is what you should be climbing at for the initial climbout.

In the twins I'll tend to accelerate to a bit above blue line (which happens to be around Vy) and then do my initial climb out at that. Continued climb speed depends on the required climb rate and conditions. Full power to 1,000 AGL, and then reduce to climb power (if applicable - sometimes climb power = full power).
 
Rob58 said:
Would like to get some opinions... on a departure what is more valuable in case of a power loss: airspeed or altitude?
Click to expand...

Highly dependent in what you are flying and at what point you are in the departure. The lower you are, the more important speed is. Enough height and safe speed can be obtained. Too low and you can trade any excess speed for height. Height give you time to try and sort out what's wrong and make an informed decision.
 
FastEddieB said:
The problem with "airspeed" is that parasitic drag increases as the square of the increase in velocity. Achieving a bunch of extra airspeed with the intent of a "zoom climb" if something goes wrong will always put you at a lower altitude than just climbing at Vy or Vx as appropriate, and hence give you fewer options.

So: altitude.
Click to expand...

What he said.
 
Well, once you loose power you can always gain airspeed but you can rarely gain altitude!
 
Shawn said:
Well, once you loose power you can always gain airspeed but you can rarely gain altitude!
Click to expand...

The only way you won't gain altitude is if you are right on the edge of a stall to start with.
 
In the twin, airspeed. Lose one engine below blue line and the crash at the crash site inverted. Lose one engine above blue line and land at the crash site in control and right side up.
 
Great feedback... like Rotordude said "energy" - or the storage of reserve energy - seems to be ultimate goal. A lot of good points offered, some of which I hadn't considered. Thanks!
 
Isn't there an old pilot's cliche about "nothing more useless than air above you and runway behind you"...

(although I think we can add to that list "Cessna seat rails" and "GA fuel gauges")
 
As long as my airspeed is at or above Vbg, I want altitude.

The next question is usually Vx or Vy. In most cases I want ALTITUDE per time (Vy).
 
flyingron said:
As long as my airspeed is at or above Vbg, I want altitude.

The next question is usually Vx or Vy. In most cases I want ALTITUDE per time (Vy).
Click to expand...

That.

Altitude is more flexible storage of energy. Other than the cases where you have a twin and need to be above blue line or you're clearing an obstacle at Vx, you should climb out at Vy at least to a safe altitude.

As others have noted, airspeed incurs drag proportional to the square of the airspeed. Altitude has no such restriction. So altitude is going to be the most efficient way to store energy for a given amount of power.

Physics! It's not just for school!

John
 
Airspeed or altitude? I suppose the importance of one depends on how little you have of the other. Whether kinetic or potential, it's energy. They're really the flip sides of the same coin.
 
You must log in or register to reply here.
Back
Top